Laptop-computer battery question

[Super Firebug]

I generally use my laptop running off the power cord, without the battery in it. Sometimes, I need to move it into another room when I'm in the middle of working on something on it, which means saving my work and shutting the computer down. Does anyone know if it's safe to snap the battery in - or remove it - while the computer's on? I mean, safe for the computer AND the battery. If it is, that'd save me time and aggravation. (I rarely run it off the battery, because recharging it will eventually wear it out, and I really don't want to have to find a way to spare the money to replace it. Yes, my finances are THAT bad.)

[chuckv3]

Why not just leave the battery in? I don't get why you would feel the need to operate without the battery in there. On some laptops it actually won't work, since the battery also serves as a voltage regulator. I guess it does work on yours, but still -- why?

Are you worried about battery life? That's not a valid concern. They go from optimal to meh in 3 to 5 years no matter what you do. I used to buy spare batteries for my netbook for airplane trips, and even the "secondary" battery (bought at the same time as the primary), which was used maybe 3 or 4 times per year, died at about the same rates. You can make them perform a little better if about every 6 months you let them run down to zero and then plug them in again. Even the 10-year old laptop I have for watching TV in bed will hold a charge for 10 minutes when unplugged, which is way more than enough to move from room to room.

Are you worried about extra electricity having the battery there? It's probably less than a 1% difference, so why bother.

[Arcana]

(I rarely run it off the battery, because recharging it will eventually wear it out, and I really don't want to have to find a way to spare the money to replace it. Yes, my finances are THAT bad.)

You're probably thinking of the old "memory effect" of nickel cadmium batteries.  Modern lithium ion batteries don't have that effect.  Keeping the battery in the laptop constantly will not cause trickle charging to reduce the capacity of the battery.

There *is* a small advantage to removing the battery, but it is not the one you're thinking of.  The biggest stress on modern lithium batteries is heat: the hotter they are, the faster they lose their charging lifetime, and ironically this effect is stronger when the battery is at full charge than when it is at low charge.  However, unless your laptop runs extremely hot, the effect is probably not worth the headache of constantly removing and replacing the battery.

Most modern laptops do allow you to hot plug the battery, but I don't recommend doing that often.  You're just as likely to wear out the battery contacts through constant swapping than the battery capacity itself.  Regardless, as chuckv3 states, nothing you do will keep the battery perfect forever, and if the only reason you need the battery is to keep the laptop powered for the few minutes it takes to move it to another room then I'd just keep the battery in.  Even at 10% capacity that's more than enough time to do that.  A laptop battery is likely to contain enough charge for a room move for seven to ten years (in three to five you probably don't want it powering your laptop at a Starbucks without AC power) and you can get third party replacements for $50-$75.  75 bucks every ten years is almost certainly less than what you're paying in electrical costs to power the laptop.

A word on deep discharge.  Don't do it.  I know chuckv3 recommended doing that every six month.  I strongly advise against it.  Some people recommend doing a battery meter calibration cycle on the laptop so you know the battery fuel gauge is accurate, and if that's important to you go ahead.  But given how you're using it, I don't think the fuel gauge is all that important.  Lithium ion batteries do not like deep discharge.  Every deep discharge you do is probably hurting the battery as much as couple months of shallow discharge usage.  The NiCads used to like that.  Lithium ion does not.

[Super Firebug]

What I'm talking about is that I've read that any rechargeable battery can only be recharged so many times before it fails to even take a charge. It's like fatiguing metal by bending it back and forth: the metal will get progressively weaker with each bend, until it finally fails. The battery can only be recharged so many times before it wears out, and will no longer work as a battery. So I prefer to use the battery only when I need a battery.

As to memory effect, I found this: http://m.phys.org/news/2013-04-memory-effect-lithium-ion-batteries.html

[Arcana]

What I'm talking about is that I've read that any rechargeable battery can only be recharged so many times before it fails to even take a charge. It's like fatiguing metal by bending it back and forth: the metal will get progressively weaker with each bend, until it finally fails. The battery can only be recharged so many times before it wears out, and will no longer work as a battery. So I prefer to use the battery only when I need a battery.

That's true for all batteries, but the point is that is not the *only* way batteries degrade.  Do you store your battery at 68 degrees F?  If not, it is probably degrading on the shelf.  Do you store your battery at full charge?  If so, it is also degrading in that state.

Also, lithium ion batteries don't exactly wear out in the way you describe.  Its more of an asymptotic curve than a breakage limit, like say flash memory.  Batteries don't fail, they get progressively weaker.

As to memory effect, I found this: http://m.phys.org/news/2013-04-memory-effect-lithium-ion-batteries.html

That memory effect is not the same one as in NiCad, more importantly you're quoting a physics article: the practical problem is the deep discharge necessary to erase that effect is more harmful to the battery than the benefit of erasure in most cases.  It is pretty much gospel in the power protection biz that deep discharge of things like modern UPSs are the ultimate killer of batteries, outside of overheat.  I should also point out that Tesla car power systems explicitly prevent full discharge because it is known to significantly reduce the lifetime of the battery - you literally cannot burn the last 20% of the power pack: it will shut down the car.  The trick to preventing the batteries from degrading too quickly was to create a power pack significantly larger than necessary and then not using all of it.  Keeping the battery between 20% and 90% increased the lifetime of the battery substantially over allowing the battery to charge to 100% and then deplete to (near) zero.

[Felderburg]

...without the battery in it.

I had no idea that was even possible!

What I'm getting from this thread, though, is that it may be a bad idea to leave my laptop plugged in all the time, since I use it as my main desktop compy. Yes, I take it places and its charge drops since I'm using it as a portable device, but 90% of the time it's sitting there plugged in.

[Ironwolf]

What type of laptop do you have?

I do occasionally have a spare I can get a hold of. I leave batteries in because it is a built in UPS.

[Super Firebug]

I had no idea that was even possible!

Yeah, I surprised my sister with that one, too.

To Ironwolf: it's an HP Pavilion g-series notebook- a g6-1c58dx, to be precise, according to the sticker that's still beside the touchpad after all these years.

[Manga]

Lithium-based batteries (LiOn and LiPo) like to be abused.  The worst thing you can do to them is leave them sitting idle without any recharging.  So leave the battery in the laptop, and the normal charging cycles will keep the battery healthy for years.

[Codewalker]

I had no idea that was even possible!

I used to do that with some old laptops that the battery didn't work anyway and I was using as a dumb terminal.

If the battery works, though, I'll leave it in just to have a built-in UPS. The rule of thumb I've always heard to get maximum battery life out of Lithium Ion is "charge early, charge often". They really don't like to be discharged all the way, and that'll eventually happen even if it's sitting on a shelf. Keeping it at about 90% by trickle charging is the ideal case for maximizing their life, assuming no extreme environmental conditions.

[Arcana]

Lithium-based batteries (LiOn and LiPo) like to be abused.  The worst thing you can do to them is leave them sitting idle without any recharging.  So leave the battery in the laptop, and the normal charging cycles will keep the battery healthy for years.

The worst thing you can do to lithium ion, so I've been told, is to charge them to absolute full, then leave them lying around in a non-climate controlled environment that consistently gets above 90 degrees F.

The best thing you can do if you're not going to use them for a long time is discharge them to below 50% (but above 10%) then store them in a climate controlled environment around 60 degrees F. 

By in large, though, lithium ion batteries are designed to be used continuously, and while they have a usage lifetime not using them doesn't extend their lifetime dramatically unless you do so in very specific ways.